Billing for rendered services, such as telecommunications services, Internet services, etc., can be provided through automated billing processes and systems. Errors in automated billing processes and systems can occur when billing details are changed, such as when a promotional product or service is unintentionally dropped by a billing system, when one-time occurrence charges are entered incorrectly, etc. Such errors may generate bills that change by more than a particular amount or percentage, bills that are missing promotional information that should be applied, etc. These errors in automated billing processes and systems can lead to customer dissatisfaction, delays in payments, and customer service costs.